This invention relates to improvements in a balancer system for a power plant including a reciprocating engine, having a balance shaft for reducing vibration generated under the action of a reciprocating inertia mass.
Hitherto a variety of balancer systems for reciprocating engines have been proposed and put into practical use, in which a balance shaft or balance shafts are rotatably installed to the engine which is combined with a transmission to constitute a power plant. One of them is disclosed in Japanese Patent Provisional Publication No. 5-172187. In this conventional balancer system, a distance (L.sub.F) between the center of gravity of the power plant and the center of inertia force generated by the engine is smaller than a distance (L.sub.X) between the center of gravity of the power plant and the center of inertia force generated by the balance shaft, on a plane containing the axis of a crankshaft of the engine. This is intended to balance moments due to the both inertia forces and acting around the center of gravity of the power plant.